NRF52810-QFAA-R datasheet(374/483 Pages) NORDIC

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Peripherals

received. If TXD.MAXCNT is larger than RXD.MAXCNT, the superfluous received bytes will be ignored. If

RXD.MAXCNT is larger than TXD.MAXCNT, the remaining transmitted bytes will contain the value defined

in the ORC register.

If RXD.PTR and TXD.PTR are not pointing to Data RAM region, an EasyDMA transfer may result in a

HardFault or RAM corruption. See Memory on page 15 for more information about the different memory

regions.

The .PTR and .MAXCNT registers are double-buffered. They can be updated and prepared for the next

transmission immediately after having received the STARTED event.

The ENDRX/ENDTX events indicate that EasyDMA has finished accessing the RX/TX buffer in RAM

respectively. The END events are generated when both RX and TX are finished accessing the buffers in

RAM.

EasyDMA supports the following list types:

• Array list

6.18.3.1 EasyDMA array list

The EasyDMA array list can be represented by the data structure ArrayList_type.

For illustration, see the code example below. This data structure includes only a buffer with size equal to

Channel.MAXCNT. EasyDMA will use the Channel.MAXCNT register to determine when the buffer is full.

Replace 'Channel' by the specific data channel you want to use, for instance 'NRF_SPIM->RXD', 'NRF_SPIM-

>TXD', 'NRF_TWIM->RXD', etc.

The Channel.MAXCNT register cannot be specified larger than the actual size of the buffer. If

Channel.MAXCNT is specified larger than the size of the buffer, the EasyDMA channel may overflow the

buffer.

This array list does not provide a mechanism to explicitly specify where the next item in the list is located.

Instead, it assumes that the list is organized as a linear array where items are located one after the other

in RAM.

#define BUFFER_SIZE 4

typedef struct ArrayList

{

uint8_t buffer[BUFFER_SIZE];

} ArrayList_type;

ArrayList_type MyArrayList[3];

//replace 'Channel' below by the specific data channel you want to use,

for instance 'NRF_SPIM->RXD', 'NRF_TWIM->RXD', etc.

Channel.MAXCNT = BUFFER_SIZE;

Channel.PTR = &MyArrayList;

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